Someone told me George Van Eps computed the number of chord combinations in his book “Harmonic Mechanisms for Guitar” and it came out to 364 million chord possibilities. I found that Ted Greene made a reference to it in an interview with GVE linked below, but it is only mentioned in passing.
I attempted some of my own calculations, but it misses the mark. I even tried if Greene confused million with billion.
If I assume 24 frets on a 6-string guitar, plus open strings and muted strings adding two more notes, it should be 26^6 = 308,915,776 = 308 million.
If I assume the result should be 364 billion, on an 8-string guitar you might calculate 26^8 = 208,827,064,576 which is around 209 billion.
So none of these results suggests 364 million or 364 billion.
I'm not sure if what he had in mind was specific to the guitar or not, but he wrote books for 6-string guitar and played a 7-string guitar himself.
Can anyone elaborate on how GVE came up with the figure?
I also got this idea about how many melodies you can make out of n notes from here https://plus.maths.org/content/how-many-melodies-are-there
The formula is
f(n) = 13^n-(13-1)^n
If we use an octave we have 8 notes out of a possible 13.
f(8) = 13^8-(12)^8 = 385,749,025 = 386 million
I think this is the closest I can get to the suggested 364 million possibilities.